The present invention relates to energy usage and, and more specifically, the usage and recharging of electric power in a vehicle based on the source of the power.
Hybrid vehicles combine a conventional internal combustion engine (ICE) and an electric motor. The electric motor is driven by rechargeable batteries. The batteries can be charged by the ICE (when running) or by regenerative braking of the electric motor. A particular type of hybrid vehicle, referred to as a “plug-in hybrid electrical vehicle” (PHEV), includes a third manner of charging the batteries. In particular, PHEVs include a plug or other implement that allows the batteries to be charged from an external electrical power source (e.g., the power grid). Thus, both liquid fuels (e.g., gasoline or diesel used by the ICE) and the electrical power grid can provide power for recharging the batteries.
In view of the fact that electrical power can be produced in several different manners, the range of actual energy sources for recharging the batteries is virtually limitless. These sources include, but are not limited to, gasoline, diesel, ethanol, plants that produce electricity by burning coal or other fossils fuels, nuclear power plants, solar or wind power generation facilities or hydroelectric sources.
In the context of external power sources, the electricity used to recharge the battery can actually come from many sources, depending on the time of day or location of the vehicle. For example, in one region of the country, hydroelectric power may be prevalent. This is a form of “clean” energy. However, in another region of the country, coal may be used. Thus, the recharging of electric vehicle batteries may be considered relatively “green” (e.g. low carbon creation) or “not green” (e.g. high carbon creation) depending on the location of the vehicle. This means that the same vehicle might be considered to have low environmental impact or high environmental impact depending on the source of electricity used to charge the batteries.